1. Field of the Invention
The present invention relates to a coupling arrangement for coupling a driving unit to a driven unit.
2. Description of the Related Art
It is known to mount between driving and driven units different types of couplings which break the connection between said units when overloading occurs. If the driving unit tends to race when the load is disconnected, the revolutionary speeds on the driving side may become so great as to cause damage to the driving unit. For instance, when driving generators with the aid of steam or gas turbines, load peaks occur in the event of phase synchronization errors or short-circuits such as to necessitate the connection between turbine and generator to be broken immediately. However, when a small rotating mass is found on the turbine side of the coupling, the steam or gas turbine that was connected by the coupling may already have been seriously damaged or wrecked before the turbine drive has had time to switch off, i.e. within the space of one-half to one second. In the case of a water turbine that rotates at a speed of 120 rpm, for instance, and drives a generator through gearing at a speed of, e.g., 1500 rpm, the failure of a shear coupling mounted between the gearing and the generator with subsequent racing of the turbine, e.g. to a speed of 240 rpm, can wreck or seriously damage the gearing.